深圳笔架山水厂优化节水的实验研究

针对目前我国城镇需水量大、原水费用高的问题,大多数水厂通过降低自用水量的方式节约水资源。经过在笔架山水厂进行的生产性实验,优化耗水工艺的运行条件,挖潜了该水厂的节水空间,自用水量降低。优化后,全处理系统可节约水资源76.83万m3/a,耗水率由原来的2.08%下降到1.49%,同时水厂的经济效益也得到了显著提高,优化后可在原来的基础上节约运行成本近60万元/a。     

Methyl tert-butyl ether (MTBE) in finished drinking water in Germany

In the present study 83 finished drinking water samples from 50 cities in Germany were analyzed for methyl tert-butyl ether (MTBE) content with a detection limit of 10 ng/L. The detection frequency was 46% and the concentrations ranged between 17 and 712 ng/L. Highest concentrations were found in the community water systems (CWSs) of Leuna and Spergau in Saxony-Anhalt. These CWSs are supplied with water possibly affected by MTBE contaminated groundwater. MTBE was detected at concentrations lower than 100 ng/L in drinking water supplied by CWSs using bank filtered water from Rhine and Main Rivers. The results from Leuna and Spergau show that large groundwater contaminations in the vicinity of CWSs pose the highest risk for MTBE contamination in drinking water. CWSs using bank filtered water from Rhine and Main Rivers are susceptible to low MTBE contaminations in finished drinking water. All measured MTBE concentrations were below proposed limit values for drinking water.     

Evaluating the exchange of DDTs between sediment and water in a major lake in North China

A large-scale sampling program was conducted to simultaneously collect surface water, overlying water, pore water, and sediment samples at monthly intervals between March and December 2010 from Baiyangdian Lake, North China to assess the distribution of DDTs and determine the net direction of sediment–water exchange. Total DDT concentrations ranged 2.36–22.4 ng/L, 0.72–21.9 ng/L, 2.25–33.7 ng/L, and 4.42–7.29 ng/g in surface water, overlying water, pore water, and sediments, respectively, which were at the intermediate levels compared to those of other area around the world. Seasonal variations of DDTs were featured by higher concentration in summer. This was likely associated with (a) the increase of land runoff in the summer and (b) application of dicofol and DDT-containing antifouling paints for ships in summer. Sediment–water fugacity ratios of the DDT isomers were used to predict the direction of the sediment–water exchange of these isomers. The sediment–surface water, sediment–overlying water, and sediment–pore water fugacity ratios of DDT isomers averaged 0.34, 0.44, and 0.1, which are significantly lower than the equilibrium status (1.0), suggesting that the net flux direction were from the water to sediment and the sediment acted as a sink for the DDTs. The difference of DDT concentrations between sediment and water samples was found to be an important factor affecting the diffusion of DDT from the water to sediment.     

冬季不同生境下菹草的水质净化效果研究

在室外通过人工构建静态模拟生态系统,研究冬季不同底质、水深、水质条件下,菹草对水体营养盐的吸收净化效果。结果表明,在不同水深或水质污染程度的相应组实验中,添加土壤改良剂的各组实验的TN、TP、NO3--N、高锰酸盐指数去除率均高于相应的未添加组,而NH4+-N去除情况相反;添加土壤改良剂有助于菹草对水体营养盐的综合去除,菹草在水深较深且营养盐负荷较高的水体中对营养盐的去除效果更好;水深35cm比水深25cm更适宜菹草的生长;菹草在实验设计的水质条件下能正常生长和对水质进行高效净化,适合在冬季运用于一般河道的水体修复。     

关于水质采样中的质量控制措施

水质采样在水环境保护工作中发挥着非常重要的作用,对水质监测结果有着非常直接的影响。文中将探讨水质监测当中经常存在的问题,并提出一些有效的质量控制措施,进一步保证水质采样的结果。为此,笔者在文中对水质采样中的质量控制措施进行探讨,希望对促进中国水环境保护事业的发展,可以起到有利的作用。     

Distribution of polycyclic aromatic hydrocarbons in surface water and sediment near a drinking water reservoir in Northeastern China

The levels of polycyclic aromatic hydrocarbons (PAHs) in the water and the sediment samples collected near the Mopanshan Reservoir—the most important drinking water resource of Harbin City in Northeast China—were examined. A total of 16 PAHs were concurrently identified and quantified in the three water bodies tested (Lalin River, Mangniu River, and Mopanshan Reservoir) and in the Mopanshan drinking water treatment plant during the high- and low water periods. The total PAH concentrations in the water and sediment samples ranged from 122.7 to 639.8 ng/L and from 89.1 to 749.0 ng/g dry weight, respectively. Similar spatial and temporal trends were also found for both samples. The lowest Σ₁₆PAH concentration of the Mopanshan Reservoir was obtained during the high water period; by contrast, the Lalin River had the highest concentration during the low water period. The PAH profiles resembling the three water bodies, with high percentages of low-molecular weight PAHs and dominated by two- to three-ring PAHs (78.4 to 89.0 %). Two of the molecular indices used reflected the possible PAH sources, indicating the main input from coal combustion, especially during the low water period. The conventional drinking water treatment operations resulted in a 20.7 to 67.0 % decrease in the different-ringed PAHs in the Mopanshan-treated drinking water. These findings indicate that human activities negatively affect the drinking water resource. Without the obvious removal of the PAHs in the waterworks, drinking water poses certain potential health risks to people.     

Hydrochemical stratification in flooded underground mines: an overlooked pitfall

The fact that flooded underground mines are commonly hydrochemically stratified is often not appreciated. Water samples taken from the water surface in partly flooded shafts are often wrongly assumed to represent the water quality existing throughout the entire water column. In some cases, treatment systems have been designed on the basis of these often misleading water surface samples. Stratification can build up within a slowly recovering system where there are few lateral inflows and outflows to the system. Less mineralised, shallow-sourced water enters at the top of the water column and more heavily mineralised water tends to remain at the base of the water column. This water has a high dissolved solids content due to dissolution of increasing amounts of pyrite oxidation salts and other minerals as the water level rises through the old workings. However, such stratification can easily be lost following hydraulic disturbance of the system (either by pumping or by natural decant when the water level reaches an outflow pathway from the mine system, such as an old adit or shaft collar) and often results in surface discharges of poor water quality. Test pumping of one such stratified system (Frances Colliery, Scotland) has provided useful information about how stratified systems develop, and how they can behave when disturbed. The water quality observed after stratification was disturbed by pumping was worse than would have been anticipated on the basis of water samples taken from the surface of the water column prior to pumping (with concentrations of contaminants such as iron and zinc being around two orders of magnitude greater than in water surface samples). Taken together with other information from the literature, the experience at Frances Colliery supports the proposal of criteria for recognising when stratification of mine water quality might be anticipated, thus facilitating the timely deployment of measures required for its detection at an early stage.     

Water quality and health in northern Canada: stored drinking water and acute gastrointestinal illness in Labrador Inuit

One of the highest self-reported incidence rates of acute gastrointestinal illness (AGI) in the global peer-reviewed literature occurs in Inuit communities in the Canadian Arctic. This high incidence of illness could be due, in part, to the consumption of contaminated water, as many northern communities face challenges related to the quality of municipal drinking water. Furthermore, many Inuit store drinking water in containers in the home, which could increase the risk of contamination between source and point-of-use (i.e., water recontamination during storage). To examine this risk, this research characterized drinking water collection and storage practices, identified potential risk factors for water contamination between source and point-of-use, and examined possible associations between drinking water contamination and self-reported AGI in the Inuit community of Rigolet, Canada. The study included a cross-sectional census survey that captured data on types of drinking water used, household practices related to drinking water (e.g., how it was collected and stored), physical characteristics of water storage containers, and self-reported AGI. Additionally, water samples were collected from all identified drinking water containers in homes and analyzed for presence of Escherichia coli and total coliforms. Despite municipally treated tap water being available in all homes, 77.6% of households had alternative sources of drinking water stored in containers, and of these containers, 25.2% tested positive for total coliforms. The use of transfer devices and water dippers (i.e., smaller bowls or measuring cups) for the collection and retrieval of water from containers were both significantly associated with increased odds of total coliform presence in stored water (OR_{transfer device} = 3.4, 95% CI 1.2–11.7; OR_dipper = 13.4, 95% CI 3.8–47.1). Twenty-eight-day period prevalence of self-reported AGI during the month before the survey was 17.2% (95% CI 13.0–22.5), which yielded an annual incidence rate of 2.4 cases per person per year (95% CI 1.8–3.1); no water-related risk factors were significantly associated with AGI. Considering the high prevalence of, and risk factors associated with, indicator bacteria in drinking water stored in containers, potential exposure to waterborne pathogens may be minimized through interventions at the household level.     

Analysis of polychlorinated dibenzo-p-dioxins and furans in various aqueous samples in Taiwan

Twenty-one fresh water samples were taken from reservoirs, wells and drinking water treatment plants in Taiwan for measurement of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) concentrations. Due to low concentration of PCDD/Fs, water samples (400-1000 L) were collected by using the on-site large volume pre-concentration system and analyzed by high resolution gas chromatography (HRGC)/high resolution mass spectrometer (HRMS). Different characteristics of dioxin profiles in surface water and groundwater are observed. The PCDD/F concentrations in fresh water samples varied from 0.001 to 0.265 pg WHO₉₈-TEQ/L which are lower than the standard (12 pg WHO₉₈-TEQ/L) set by the Taiwan Environmental Protection Administration (TEPA) for drinking water. Only a small fraction (<5%) of the total PCDD/F concentration in fresh water samples was water-soluble. As a result of their hydrophobicity, PCDD/Fs are effectively removed along with suspended solid via the water treatment process (average 98% removal efficiency).     

The mutagenic potentials of tap water samples in Shanghai

The tap water samples were collected from the users' ends in several areas of Shanghai, which is located in Taihu Lake basin, Eastern China. Source water samples were also collected from two municipal source water facilities at the same time. Samples were assayed by three different short-term mutagenicity test systems: Salmonella/microsome assay (Ames test), the Arabinose resistance test (Ara test) and the SOS/umu test. The data showed that two source water samples did not display direct mutagenic potentials. Two tap water samples from city north, which were directly from Yangtze River, were also not mutagenic. Water samples from city south and middle which used source water originating from Taihu Lake were proved to be contaminated with mutagenic potentials by three different assay techniques. The boiled water displayed an even stronger mutagenic potential compared to its original tap water. The molecular mechanism of mutagenicity was associated with a reading frame-shifting potential. GC-MS analysis of tap water extracts from city middle and corresponding source water was compared. Qualitatively similar spectra were observed except for the peaks of three chlorinated aromatic hydrocarbon compounds, which existed only in the tap water. Since the water source has been polluted, raw water was heavily chlorinated in order to sterilize. More toxic compounds, including mutagens, might form during the multi-chlorination. Caution about the possibility of elevated cancer risks in the population that consumes heavily chlorinated water should be kept in mind. A cohort study in the residents of Shanghai is required.     

美国加州再生水利用经验剖析及对我国的启示

开发利用再生水具有巨大的社会经济价值,是实现可持续发展的重要环节.在美国加州,再生水利用已经成为其水资源的重要组成部分,具有详细的规划、系统地法律法规和完备的管理体系,走在了世界的前列.总结分析了加州再生水利用相关的法律法规与灌溉终端用户管理的一些经验,并对2个典型案例进行了剖析.科学的再生水利用规划、严格的源水水质控...     

多水源供水管网中铁释放规律

针对水源切换而引起的水质超标现象,开展了多水源联合供水条件下管网中铁释放规律的研究。分析了北方某城市2种水源(滦河水和长江水)的水质特点,利用实验模拟反应器分别研究了水源完全置换和供水分界线处水源混合区域的铁释放规律。结果表明,多水源供水管网的铁释放速率与水源水质密切相关,特别是水中含高浓度SO2-4和氯化物时会加快铁的释放。不同水源之间的频繁切换会破坏管垢表面的钝化层,使铁释放速率迅速变化,随后会有所缓解,但新的平衡的形成需要较长时间。供水分界线处的水源混合区域,由于水质的不断变化造成管垢表面很难形成稳定的钝化层,铁释放速率持续偏高,只有当长江水所占比例高达75%以上时才能得到抑制。     

Controlling residential water demand in Qatar: an assessment

Qatar has serious water resource problems, following rapid socioeconomic development and massive population increase. Municipal water provision depends on costly and unsustainable desalination. There is little regulation. Native Qataris do not pay a water tariff and migrants pay a subsidized price--approximately one third of the cost of production--so there is little awareness of the true cost of water and use is profligate. This paper discusses trends in water use and identifies issues underlying sustainable water use in Qatar. A questionnaire of respondents chosen to represent Qatari social groups measured awareness and attitudes to water. The results show that previous efforts to control water demand in Qatar, using awareness campaigns, legal restrictions and tariffs, have been ineffectual. The questionnaire evaluated reactions to possible measures to limit uses by raising awareness, using legal restrictions and raising tariffs. From this, a number of policy changes can be suggested, to bring Qatar's water industry towards sustainability.     

Water transformation in the media of biofilters controlled by Rhodococcus fascians in treating an ethyl acetate-contaminated airstream

Biofilters do not provide much water for bacteria to grow. To use them efficiently and properly, it is essential to understand the kinetics of water transformation and to control moisture levels. This study aims to clarify whether the metabolism of microorganisms will improve the water-holding capacity of media or will intensify drying. This experiment was conducted in duplicate, that is, both with and without bacterial inoculation. Both the constant water content mode and the declining water content mode show that microbial growth in a log phase will enhance drying. In contrast, the bacteria growing in a logarithmic decline phase will improve water-holding capacity. Basically, water evaporation can result from the latent heat obtained from microbial respiration or from the physical temperature difference between the unsaturated air and the wet media. Two ways that biofilters can gain water are from water incorporated into bacteria cells and from water obtained from the oxidation of volatile organic compounds (VOCs).     

Water Transformation in the Media of Biofilters Controlled by Rhodococcus fascians in Treating an Ethyl Acetate-Contaminated Airstream

Abstract

Biofilters do not provide much water for bacteria to grow. To use them efficiently and properly, it is essential to understand the kinetics of water transformation and to control moisture levels. This study aims to clarify whether the metabolism of microorganisms will improve the water-holding capacity of media or will intensify drying. This experiment was conducted in duplicate, that is, both with and without bacterial inoculation. Both the constant water content mode and the declining water content mode show that microbial growth in a log phase will enhance drying. In contrast, the bacteria growing in a logarithmic decline phase will improve water-holding capacity. Basically, water evaporation can result from the latent heat obtained from microbial respiration or from the physical temperature difference between the unsaturated air and the wet media. Two ways that biofilters can gain water are from water incorporated into bacteria cells and from water obtained from the oxidation of volatile organic compounds (VOCs).     

岩溶水系统中微生物迁移机制

对桂林罗锦响水岩岩溶水系统雨前、雨中和雨后水中及悬浮物上携带的细菌数量变化规律分析表明,在雨期,岩溶地下河水质变化对地表水质响应迅速,表现为在一定时期内地下水与地表水中的细菌总数可达到同一个数量级;地下水中TSS与细菌总数的变化具有一致性,即细菌总数随TSS的升降而升降,说明细菌大多是附着在悬浮颗粒物运移的;同时,岩溶区地下河局部存在的溶潭等蓄水构造对污染物具有明显的纳污与稀释效应,是岩溶地下河系统产生自净作用的主要场所。TSS与地下水流速呈正相关,而附着在悬浮颗粒物上的细菌占地下水中细菌总数的比例与流速呈负相关。地下河洞口的堆积物对微生物具有明显的截留作用,其对微生物的吸附和缓慢释放,是导致地下河在很长一段时间内都会受到微生物污染的主要原因。     

净水厂滤池反冲洗水回用的贾第鞭毛虫和隐孢子虫的泄漏问题研究

采用美国EPA1623方法,研究滤池反冲洗水回用的贾第鞭毛虫和隐孢子虫泄漏问题.通过检测某水厂原水、出厂水和滤池反冲洗水中贾第鞭毛虫和隐孢子虫数量,表明该厂水源未受到贾第鞭毛虫和隐孢子虫的污染,但输送过程易造成水质的污染.滤池反冲洗水中只检出贾第鞭毛虫,出厂水中未检出贾第鞭毛虫和隐孢子虫,说明该厂滤池反冲洗水直接回用未造成"两虫"泄漏问题.     

沭阳县水环境安全管理与污染防治对策探讨

在简要介绍沭阳县水环境概况后,着重分析了该县的水污染现状和主要的水环境问题,并针对性地提出了一些水环境安全管理和污染防治的建议,建立淮河流域水环境安全协调机制和沭阳水环境保护机制,完善水质监测,加强工业、农业和生活污染的防治,建立清污分流系统,并加强宣传教育等项工作.     

Impact of intermittent water supply on water quality in Lebanon

Lebanon in general and its capital, Beirut, suffer from water shortage due to the increasing water demand and the lack of proper management despite its abundant water resources. An intermittent water supply strategy was implemented in order to minimise deficiency problems. This, however, can seriously affect water quality due to the potential suction of non-potable water by negative pressures, biofilm detachment, and microbial re-growth especially when static conditions occur. Intermittent supplies also entail storing water in household tanks to satisfy demand during no-flow periods, and these tanks often encourage bacterial re-growth. Dumping of disinfectants in order to circumvent bacterial presence and the subsequent formation of undesirable byproducts is another concern. A study was conducted in Beirut over an eight-month period, during which samples were collected from household tanks and drinking water taps of Beirut's network. This paper presents the findings of the study and highlights key aspects in intermittent water supply systems.     

Perfluorooctanesulfonate and perfluorooctanoate in raw and treated tap water from Osaka, Japan

Perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) have been recognized as emerging environmental pollutants because of their ubiquitous occurrence in the environment, biota, and humans. PFOS and PFOA have been detected in water in Japan. Nevertheless, occurrence of PFOS and PFOA in potable water from municipal water treatment plants is not clearly known. We analyzed PFOS and PFOA in raw and tap water samples collected from 14 drinking water treatment plants in winter and summer seasons in Osaka to determine the concentrations of PFOS and PFOA in raw and potable tap water samples. PFOS and PFOA were detected in all raw water samples. Concentration ranges of PFOS and PFOA in raw water were 0.26-22 ng/l and 5.2-92 ng/l, respectively. Whereas the concentrations PFOS in raw water from Osaka were similar to those in other areas in Japan, the concentrations of PFOA were higher than in other areas. Concentration ranges of PFOS and PFOA in potable tap water were 0.16-22 ng/l and 2.3-84 ng/l, respectively. There were positive correlations between PFC concentrations in raw water and tap water samples. Therefore, the removal efficiency of PFCs by the present water treatment may be low. Based on the current action value reported by U.S. Environmental Protection Agency, PFOA concentrations found in tap water in Osaka is not expected to pose health risks.